Patients with certain illnesses like diabetes, must verify several times a day the sugar content of their blood.
According to this content, the patient must or must not take certain medicines.
Since such tests have to be made frequently, it is indispensable that the patient has with him a portable device which he can easily and safely operate, because he may not be able to get help from a third person and is even less likely to find a laboratory which specializes in such tests.
For this reason, portable devices already exist, but they are not entirely satisfactory, particularly with respect to their size and easy handling.
For example, a device is known which comprises a body and a pin-carrying, movable holder which pivots relative to the body according to a movement which resembles that of a hammer in firearms and is acted upon by a spring toward its active position.
The holder is outside of the body, and since it carries the pin, the latter can accidentally injure the user even when the device is not in use, i.e. independently of any involuntary action on a control device which must be actuated to free the holder at the desired moment so that the pin is very lightly injected into the skin.
Devices are also known whose holder is inside a body but is attained by assembling half-shells of stiff synthetic material of parallelepipedal shape and is relatively bulky.
Moreover, their shape and dimensions make them unsuitable for thorough cleaning.
Also known is German Pat. No. 459.483 which describes a device of the same type as that of the present invention. However the stop m which limits the projection of the pin d outside the body a is formed by a screw nut which is more or less screwed onto a threaded shaft b in such a way that this screw nut, far from forming a foolproof fixes point, is during each use subjected to shocks against the upper portion e of the body a, thus risking an involuntary displacement which renders the coming out of the point d uncertain.
In such a structure there is no safe reference point on which the user can rely.
The user is therefore obliged to set the device by experience (and thus unreliably) each time it is to be used.
Another basic difference results from the fact that a large portion of the device is positioned outside of the body a, i.e. the threaded shaft b on its entire length, the screw nut m and a stopper without reference which is located at the end of the threaded shaft b.
This bulky device is even impractical in its design, because, since the extraction of the point d by means of the screw nut m is to be regulated, it is impossible to provide the latter inside the body a, as it would be inaccessible and invisible.